Renbatt ctesellschatt kit beschrankter haftttng



K. MAYBACH TRANSMISSION GEAR Re, 17,707

2 Sheets-Sheet 1 June 24, 1930.

OrigiLnaLFiIed March 31, 1928 Inveniar:

Y 7 K. MAYBACH TRr-NsMIssmN GEAR Re. 17,707 2 Sheets-Sheet .2

June 24, 1930.

Origin Fi'led latch 31, I928 Invenlor:

- R.......d June 24, 1930 which featurecontributes considerably to UNITED STATES PATENn OFFICE m1. lumen, or rmnnarcnswmw, GERMANY, assrexon 'ro MaYBacn-uo'ro.

BENBAU GES ELLBGHAI'T MIT BESCHRANKTER HAFTUNG,

GERMANY or rnmmucnsnunn,

rmeiussroi: GEAR Original Ho. 1,719,188, dated July 2, 1989, Serial No, 266,292, filed March 31, 1928, and in Germany Dctober 5,1927. Application for reissue filed April 15, 1930. Serial'lto. 444,587.

My invention relates to transmission gears and especially to two-speed gears in motor vehicles.

Recently there has again arisen a genera1 demand for an over-drive orover-speed in motorcars having three speeds in connection with the average axle ratio of about 5' to 1. Such an over-drive should be praetically noiseless and for this purpose internal gears were introduced. I

The main object of my invention is an over-drive having spur wheels instead of internal gears. These spur wheels in my %ear are constantly in mesh with each other. y using spur wheels it is possible to. arrange the teeth inclined and to grind them,

the efi'ect'of making the over-drive satisfactog from the stand oint of noiselessness.

nother object o my invention is to provide for a change in speed, between third and fourth speed for example, which can be effected without operating the friction clutch.

A further main object is the provision of a mechanism which may be easily attached to an automobile without necessitating any material change in the construction of the automobile.

According to my invention a special type of supplemental change speed gear is inserted. This gear comprises a direct drive and the so-called over-drive or over-speed.

' In certain cases, for example in motor busses, it will be possible'to use only the change speed gear according to my inven-. tion without having any other gear besides.

In other cases my change speed gear may be reversed so'as to slow down the speed of the vehicle as compared with the speed in direct drive. In such cases'the direct drive may be the fourth speed and the other speed the third one; this arrangement allowing also for a reduction in the rear axle ratio, for example to 3 to 1, .or the like, as circumstances may afiord.

Of course my additional two-speed gear may as'well be usedin connectionwith a gear having any number of Fig. 2 is a diagram showing the way in which the two claw couplings are constructed for the alternate connection of the driving shaft coming from the motor side,

with the driven shaft going to the differential ear. It represents a portion of the circum erence of sleeve 5 and the adjacent couplings, developed in the drawing plane, and on a larger scale.

casing 13 at 2 and its end shaped into pin,

3 \is supported within the abutting end of shaft 4. Shaft 1 extends through spur wheel 10, which is journaled in casing 13 by roller bearings 11 and 12. There is no direct connection between shaft 1 and wheel 10,

"but the latter may freely revolve around shaft 1.' Shaft 4 at its end has a spur wheel 6 in solid connection therewithor the end itself may be: shaped" into a spur' wheel. This spur wheel 6 or shaft end is supported in casing 13 by means of roller bearlngs 14 Fig. 3 represents diagrammatically the arand 15. There is a shaft 8 arranged substantially parallel to shaftsl and 4, This shaft is 1ou'rnaled in the cas ng 13 at 16 and 17 and close to these. hearings spur wheels 9 and 7, respectivel are situated and are formed integral wit shaft 8. Spur wheel 9 is in constant mesh with spur wheel 10, and.

spur wheel 7 constantly meshes with spur wheel 6. All the spur wheels have inclined teeth which are ground.

On the end of shaft land situated between wheels 10 and 6 there is mounted a sleeve 5 coupling, which halves correspond to positely situated coupling halves, an 6', respectively, belonging to wheels 10 and 6, respectively. Sleeve 5 is splined to shaft 1 so that it revolves together with this shaft and can be shifted on the shaft in its longitudinal direction. It is provided with a loose U-shaped ring 25. There is a lever 27- extending into this ring. This lever and ring are held bysprin'gs 18 and 19, and rod 20 operated by lever 21 serves ,for shifting sleeve 5 so as to engage alternately with wheel 6 or with wheel 10. Spring mechanism 22 makes it impossible for lever 21 and for sleeve 5 to rest in a neutral middle position. When lever 21-is operated spring mechanism 22 will always cause it to rest only when bearin againstone of the two stops 23 or 24.so t at spring 18 or spring19 presses the sleeve 5 towards engagement'with wheel 6 .or with wheel 10, respectively. There is no neutral position for sleeve 5 which is one-of the important features in connection with my invention. a

Another main feature is the construction of the front, faces of the projections or dogs of the claw couplings. These faces are beveled and the inclination of the faces of the right hand coupling is in the same direction as that of the faces of theleft hand coupling,

asvmay be seen from Fig. 2, so that the faces of both couplings may be called substantially parallel to eachother.

I now wantto explain the operation of the gear and the advantages connected'therewith I In the example represented wheel 10 has a larger-diameter than wheel 9 and also wheel. 7 base. larger diameter than wheel 6. This means'that inserting 'the.gear by connecting sleeve 5 to wheel 10 uses an increase in the number of revolutions and in speed from driving shaft 1 as compared to driven shaft 4, whereas engagement of sleeve 5 with wheel 6, which is the same as'with shaft 4, makesboth shafts revolve at the same speed, causing the so called direct drive.

By choosing the diameters of the wheels in relationto each. other the ratio of trans mission may be determined inany desired way, asis well known.

Assuming the direct drive had been set -which means engagement of sleeve 5 with shaft 4, and now I throw the upper arm of lever 21, bearing at'the time against stop 23,

' to the left so as to bear against stop 24 (lever position in dot-ted lines).

This operation causes lever 27 to compress spring 18 which 'tends to shift sleeve 5 to the left hand side also;'but as long as the motor gets gas the friction between the side faces 55 "and 60,0f

the right hand claw coupling prevents the two halves from coming out of engagement.

New I turn the gas off and immediately the right hand coupling is disconnected and the to engage under the tension of spring 18.

.so as to enter the gaps between the teeth of left hand coupling tends tocome into engagement. But as the two halves of the coupling have different speed, sleeve 5 turning faster than wheel lO, the projectionsor dogs do not engage but rattle past each other and would cause destruction if faces were not beveled, as shown in Fig. 2, so that the two halves of the coupling are always thrown away from each other against With the throttle closed, the speed of rothe pressure exerted by spring'18 as long as sleeve 5 revolves faster than wheel 10.

tation of shaft 1 and sleeve 5 will slow up quite rapidly, while gear 10 will continue at substantially constant speed due tothe momentum of the" car. 'As this change occurs, sleeve 5 and wheel 10 will eventually reach their front the same speed. If at the instant that the speeds equalize the teeth are properly aligned the clutch will engage; if they are not properly aligned, the speed of sleeve 5 will decrease an additional slight amount, bringing face 100 in contact with face 50, thus aligning the'clutchmembers and permitting them When one wishes to return to the direct drive, lever 21 is thrown back against stop 23. This compresses spring 19, but due to the fact that the engine'is transmitting power to the driven shaft, the frictional engagement of .the clutch prevents the shift from taking place. If the throttle is closed so that power is no longer being transmitted, sleeve-5, act ing under the tension'of spring 19, will snap over toward gear 6. Gear 6 rotates more rapidly than gear 10, and as sleeve 5 will movealmost instantaneously from contact with gear 10 into contact with gear 6, it will be rotating more slowly than gear 5. The faces of the couplings are so pitched that engagement will not takeplace while sleeve 5 1s rotating more slowly than gear. 6; thus again time with the clutch will overrun for a short out engagement. As soon as the throttle is opened, speeding up the moto1,-the, speed of sleeve 5 will increase until it equals the speed of gear 6. Unless, the teeth of gears happen at this moment to be exactly aligned, the clutch members will come into the position shown in Fig.2. As the speed of sleeve 5 increasesit will immediately begin to overrun wheel 6 and a side face 55 will bear against the side face 60 and thereuponthe teeth of sleeve 5 will be pressed by spring 19 is accomplished simply in the above described way, without operating the friction clutch, as is necessary with ordinary change speed gears. This is possible because of the way the projections of the couplings are inclined and because of there being provided means clined. It sufiices if those 0 one half, or only a limited number thereof, have th1s infor preventing the sleeve fromtaking a new tral idling position.

The front faces of the projections in the left hand coupling must be inclined in the same, direction as those in the ri ht hand coupling so that the faces may e called substantially parallel to each other. It is not necessary that the front faces of both engageable halves of the cou lings are inclination. But I prefer to provide all projections with inclined front faces.

My two-speed-gear may be applied in cars without providing any other speed gear, for example in motor busses, which besides may or may not have a possibility of oing backwards apart from my speed gear. t w ll be advisable in such cases to have a separate friction clutch in addition.

In cars having the usual change speed gear my two-speed-gear may be inserted between the motor and the ordinary change speed gear, or it may be inserted between this vgear and the differential gear, or even two gears according to my invention may be provided one between motor and ordinary change speed gear and the second one between this gear and the differential gear. This arrangement is shown dia rammatically in Fig. 3. At the left .han side .the motor M is to be seen. Next follows the first one of my gears 1,, then the usual change speed gear G, on the driving shaft S the second one of my ears I is provided, to which follows the di erential ear 1).

Of course the construction 0 my gear has to be very compact and strong, so asto avoid every unevenness in running and have a minimum of shocks and of vibration. This I attain according to' my invention by journaling the spur wheels on the drivi and on the driven shafts on both sides of the wheels s and by providing a thick stub shaft. Be-

sides I prefer to have inclined teeth on all four spur wheels, for the same purpose, and also to arrange the stub shaft 8 as close as possible to the axis of the drivingand driven shafts 1 and 4.

It is best to have the gear mechanism surrounded b a casing 13 which should be filled with oil, at or the like, so that an easy and quiet running is attained. p As explained at the beginning I think the main advantage ofmy invention will be made inicars having a usual change speed gear to which m two-speed-gear is added. This causes a ouble number of possible speeds, but the main thing is when the highest speed of the ordinary change speed gear ison my two speed gear now'allows for a further change in speed without operating "the friction clutch, simply by setting the lever, taking the gas off for a moment and then giving gas again,

I more slowlly of diiferent'size from sai between said. gears movable longitudinally My two speed 'gear may be provided in a car from the beginning. of its construction whereby, said second member is rotated at higher speed than the first member but in the same direction and in constant speed ratio withthe first member'and a 'slidable sleeve between said members substantially concentric with the axis of said members but adapted to be rotated independentlythereof;clutch mechanism whereby said sleeve may be connected with either of said members, means whereby said sleeve is at all times ten'sioned toward one or theother ofisaid members, means forming part of said clutch mechanism whereby when'said sleeve leaves the more rapidly rotating member and moves to engage with the more 'slowly rotating member,'s aid clutch mechanism will over-run and not engage so long as said sleeve is rotating more rapidly than such member, and'similar means orming part of said clutch mech anism whereby when said sleeve leaves the rotating member and moves to engage wit the more rapidly rotating'memher, said clutch mechanism will over-run and not engage so long as such member is rotat-- ing more rapidly than the sleeve.

2. In a two-speed gear mechanism of the type comprising a shaft, a ge r concentric therewith butrotatable indep ndent thereof, a second shaft substantially aligned with the first shaft and havin fixed to it a gear (I first gear, a sleeve between them but fixed to rotate with said first shaftan'd a stub shaft provided with the larger of said first two gears, having I teeth with faces so dpitched that said couplin will over-run an not engage when said sleeve is rotating faster than said ar anda second claw coupling for connectmg said sleeve with the smaller of said first two gears -having teeth with faces so pitched that said coupling will over-run and not on when said sleeve.-

3. A structure as specified in claim 2, which further includes mechanism for tensioning said sleeve-towards either of said gears under tension iiisufiicient to break the gear is rotating faster than said 4. A structure as specified in claim 2 i which further includes mechanism for tensioning said sleeve towards either of said gears and means for preventing said mechanism from holding said sleeve in neutral position.

5. In a motor vehicle in combination a motor; a rear axle gear; and a twosspeed gear, said two-speed gear comprising 'a driving shaft and a driven shaft substantially in alignment with and abutting each other, an; exceptionally sturdy stub shaft situated-substantially parallel to and closely to said first two shafts, a broad spur wheel loosely mounted on said driving shaft, a broad spur wheel rigidly fixed on said stub shaft, said two spur wheels being in constant mesh with each other, a broad spur wheel rigidly fixed on said driven shaft, a second broad spur wheel rigidly fixed on said stub shaft, said latter A two spur wheels being in constant mesh with' each other, all said four spur wheels having inclined and ground teeth, a sleeve splined to the end of said driving shaft, said sleeve having half a claw coupling at one end and half a claw cou ling at its other end, said first spur wheel Eavin half a claw coupling on its side facin sai sleeve adapted to engage with said alf 'claw coupling on said first sleeve end and forming a coupling therewith, said spur' wheel on said driven shaft having half a claw coupling on its side face infi said sleeve adapted to engage with said h f claw coupling on said second sleeve end and forming a coupling therewith, said first claw couplin h'vingl projections withinclined front aces an said second coupling also having projections with inclined front faces, all said inclinedfront faces being inclined in the same direction; ,a casing surrounding said two-speed gear; two hearings in said casing for closely journaling said first spur wheel, two hearings in said casing for closely journ'aling said spur wheel on said g9 I but fixed to rotate with said shaft, a pair of driven shaft, and two hearings in said casing for journalingsaid stub shaft at its ends and closely to said two spur wheels thereon;

and an operating mechanismfor said sleeve,

said mechanism comprising an operating lever having two rest positions only, a spring adapted to be compressed by means of said lever in one of said rest positions thereof and thereby pressing said sleeve against said first spur wheel, and a spring adapted to be compressed by means of 'said lever in the other one of said rest positions thereof and thereby pressing said sleeve against said spur wheelAfixed on said driven shaft. d1

6. change speed aring I inclu 11g a shaft, :1 pair of concenh i c gears of difl'erent pitch diameters coaxial therewith and each relatively rotatable in respect to the shaft, means operatively connecting said gears to effect simultaneous rotation at difi'erent speeds and infixed'speedratio, a sleeve between said gears slidable on said shaft but fixed against relative rotation in respect thereto, a claw coupling for. connecting said sleeve N with the larger of said gears, having teeth with faces so inclined that said coupling will overrun and not engage when said shaft and sleeve are rotating faster than said gear, and a second claw coupling for connecting said shaft and sleeve with the smaller of said gears, having teeth with faces so inclined that said coupling will overrun andnot engage when said gear is rotating faster than said shaft and sleeve.

7. A change speedgearing including a shaft, a pair of gears of different diameters coaxial therewith and rotatable in respect thereto, a countershaft having a pair of gears meshing with said first mentioned gears whereby said first mentioned gears are simultaneously rotatable at different speeds but in fixed speed ratio, a sleeve between said first gears movable longitudinally between them but fixed to rotate with said shaft, a claw coupling for connecting said sleeve with the larger of said first two gears and having teeth with end faces so pitched that said coupling will overrun and not engage when said sleeve is rotating faster than said gear, and a second claw coupling connecting said sleeve with the smaller of said first two gears and having teeth with faces so pitched that said coupling will overrun and not engage a when said gear is rotating faster than said sleeve. i

8. A change speed ring including a shaft, :1, pair of gears 0 different diameters coaxial therewith and rotatable in respect thereto, a countershaft having a pair of gears meshing with said first mentioned gears whereby said first mentioned gears are simultaneously rotatable at difi'erent speeds but in 1 fixed speed ratio, a sleeve between said first ars movable longitudinally between them claw couplings for connecting said sleeve with either of said first gears to connect the 1 coupled gear to said shaft, the end faces of the teeth of both of said claw couplings being inclined in the same direction and in such direction in res to the normal direction of rotation of said shaft that the coupling connecting said sleeve and the larger of said first gears will overrun and not engage when said sleeve is rotating faster than said gear and that the couplingconnecting said sleeve and the smaller of first gears will over- 1;:

run and not engage when said gear is rotat- 7 ing faster than said sleeve. 7

9. A change speed gearing including a shaft, a pair of concentric gears of difierent pitch diameters coaxial therewith and each relatively rotatable in respect to the shaft, means operatively connecting said gears to effect simultaneous rotation 'at different speeds and in fixed ratio, a sleeve between said 10 gears slidable on said shaft but fixed a ainst rotation in respect thereto, a pair o claw couplings for connecting said sleeve with either of said gears to connect the coupled gear to said shaft, the end faces of the teeth of both of said claw cou lings being inclined in the same direction and in such direction in respect to the normal direction of rotation of said shaft that the cou ling connecting said sleeve and the larger of said ears will overrun and not engage when sai sleeve is rotating faster than said gear and that the coupling connecting said sleeve and the smaller of said gears will overrun and not eng e when said gear is rotating faster than and sleeve. p

10. A change speed gearin including a pair of concentric gears of (Efierent pitch diameters, means operatively connecting said gears to effect simultaneous rotation at difi'erent speeds and in fixed speed ratio, a sleeve between said gears, a claw coupling for conf necting said sleeve with the larger of said gears, having teeth with faces so inclined Y that said coupling will overrun and not enas gage when said sleeve is rotating faster than said gear, and a second claw coupling for connecting said sleeve with the smaller of e v said ears, having teeth with faces so inv clinezf that said can ling. will overrun and 40 not engage when sai gear is rotating faster than said sleeve. 

